1. Field of the Invention
The present invention generally relates to a method for improving the performance of a dye laser and a device for insertion into the dye circulation stream of a dye laser in order to improve the performance thereof. More specifically, the present invention relates to a method for releasing trialkylamine into the dye circulation stream of a dye laser and a filter cartridge containing a stabilizing agent for insertion into the dye circulation stream of a dye laser in order to improve the performance thereof.
2. Description of Related Art
A major problem associated with the use of dye lasers is the light induced chemistry of the dye laser solution which produces material which absorbs at the lasing wavelength of the dye. This material then interferes with stimulated emission of the excited dye and consequently greatly attenuates the output flux of the dye laser. It has been suggested that material which potentially interferes with stimulated emission from a Coumarin 311 dye laser results from a photochemical interaction between the dye and the solvent ethanol. von Trebra, R. J; Koch, T. H., "Two-Photon laser photochemistry of a coumarin laser dye," J. Photochem. Photobiol., A:Chem., (1987), 41, pp. 111-120. The material possibly results from the initial formation of acetaldehyde and the photoprocess appears to be of a two-photon nature. The material has been proposed to bear polycarbonyl functionality.
An earlier U.S. Patent granted to a research group including one of the present inventors is directed to the stabilization of dye lasers and discloses the addition of 1,4-diazabicyclo (2.2.2)octane (DABCO) to the dye solution to quench a variety of transient species, including singlet oxygen, which is possibly involved in the formation of material which interferes with stimulated emission. The addition of DABCO improves the performance of excimer laser pumped dye lasers but not the performance of flashlamp pumped dye lasers as indicated in Fletcher, A. N.; Pietrak, M. E., Appl. Phys. B, (1985), 37, p. 151. Singlet oxygen is continuously produced by dye lasers as molecular oxygen dissolved in the dye solution serves as a quencher of triplet dye molecules. von Trebra, R. J.; Koch, T. H., "Photochemistry of coumarin laser dyes: the role of singlet oxygen in the photo-oxidation of coumarin 311," J. Photochem., (1986), 35. pp. 33-46. The resulting singlet oxygen possibly participates in the production of the material interfering with stimulated emission.
Other attempts at improving the performance of dye lasers include the use of a so-called switching dye which is used to reduce the degree of amplification for the laser radiation after a short time interval by means of transient absorption as disclosed in U.S. Pat. No. 4,807,237 to Ernsting. U.S. Statutory Invention Registration No. H437 (published Feb. 2, 1988) discloses a polydisperse aggregate of small solid particles that form voids therebetween with a lasing dye solution in said voids to form a laser host medium. U.S. Pat. No. 4,479,223 to Fletcher discloses the use of an inert cover gas, such as argon, for a laser dye solution, in combination with the employment of a glass filter, such as Pyrex, disposed between the pumping flashlamp and the dye laser cavity used to extend the effective lasing lifetime of laser dyes including coumarin dyes.
Although the above-noted attempts have been made at improving the performance of dye lasers, problems remain with regard to the production of material which interferes with the stimulated emission of the excited dye which reduces the output of the dye laser. Therefore, it is desired to provide a device which improves the performance of dye lasers by suppressing this material which interferes with the stimulated emission of the excited dye.